Past Week in Nutrition Science: This is an overview of interesting scientific articles that have been published in the past week, from last Friday (Oct 2nd) until today (Oct 9th).
Past Week in Nutrition Science (Oct 2nd – Oct 9th)
This week, we reviewed two new articles from the American Journal of Clinical Nutrition.
One was about how the body responds to a severe calorie deficit, and the other was about the effects of low-carb and high-carb diets on blood sugar control and heart disease risk factors in people with type 2 diabetes.
Study: Muller et al. Metabolic Adaptation to Caloric Restriction and Subsequent Re-feeding: The Minnesota Starvation Experiment Revisited. American Journal of Clinical Nutrition 2015.
Summary: This was a 6-week intervention study that examined the effects of severe calorie restriction on adaptive thermogenesis, also referred to as starvation mode.
The study found that adaptive thermogenesis kicks in shortly after calorie restriction starts. It appeared to have no significant effects on fat regain when the calorie restriction ended.
Study: Tay et al. Comparison of Low- and High-Carbohydrate Diets for Type 2 Diabetes Management: A Randomized Trial. American Journal of Clinical Nutrition 2015.
Summary: This was a randomized trial that compared the effects of low-carb and high-carb diets on managing type 2 diabetes. The participants were overweight or obese, and were on a weight loss diet and an exercise program.
The main conclusion of the study was that low-carb diets can lead to greater improvements in blood sugar control and blood lipid profile, as opposed to high-carb diets. There was no difference in weight loss between groups.
Other New Research From Around the World
A lot of new research came out in the past week. New issues of both the International Journal of Obesity and the European Journal of Clinical Nutrition were published.
Here is an overview of the most interesting nutrition research published in the past week, categorized by subject.
Obesity and Weight Loss
This long-term, observational study found that unintentional weight loss increased mortality in elderly, frail and disabled nursing home residents. This was regardless of whether they were overweight or obese. Unintentional weight loss is often a sign of underlying disease.
This observational study suggests that exposure to antibacterial medications before birth may increase the risk of school-aged children becoming overweight or obese.
Vitamin D deficiency before birth is possibly linked with increased risk of obesity later in life. However, this observational study indicates that the mother’s vitamin D intake is not linked to the child’s body size at age 7.
This observational study found that low-quality diet in early childhood is associated with obesity by the age of 6. A low-quality diet was defined as a diet low in fish, fruit and vegetables.
This observational study suggests that shorter sleep duration in children is associated with an increased preference for foods like fast food. This may explain the link between shorter sleep duration and childhood obesity.
Effect of whole soy and purified daidzein on ambulatory blood pressure and endothelial function—a 6-month double-blind, randomized controlled trial among Chinese postmenopausal women with prehypertension.
This double-blind, randomized controlled trial showed that consuming 40 g of soy flour or 63 g of daidzein (a soy isoflavone) per day had no significant effects on blood pressure in postmenopausal women. All of the women were equol-producing and had prehypertension or untreated hypertension.
This review study argues that the association of saturated fat and cardiovascular disease is still unclear. It stresses the importance of analyzing individual saturated fatty acids rather than assuming they are all equal. Additionally, it indicates that increased intake of palmitic acid and stearic acid may raise cardiovascular disease risk.
Blood Sugar Control and Diabetes
This crossover trial found that drinking either dairy or soy milk with white bread (co-ingestion), or 30 minutes before (preloading), reduces the rise in blood sugar after meals. Preloading combined with co-ingestion had a greater effect than co-ingestion alone.
Brain Health and Function
This double-blind crossover study indicates that eating 15-30 g of freeze-dried wild blueberries may temporarily improve cognitive performance in children.
This double-blind, randomized crossover study found that drinking Turkish coffee temporarily improved reaction performance and feels of energy, compared to decaffeinated Turkish coffee. Additionally, it increased systolic blood pressure. The Turkish coffee contained 3 mg of caffeine per kg of body weight.
Fertility and Pregnancy
Vitamins and minerals are absolutely essential for fetal growth. This observational study indicates that during the third trimester of pregnancy, birth weight is negatively associated with vitamin D intake, yet positively associated with vitamin B12 intake.
Pre-eclampsia is a complication of pregnancy characterized by elevated blood pressure and high amounts of protein in the urine. This observational study suggests that pre-eclampsia is significantly less common among women who take folic acid supplements or get high amounts of folate in their diet.
This observational study found that dental erosion and cavities were more common among vegetarians than meat-eaters. Higher fruit consumption and less use of fluoride-containing toothpaste among vegetarians may explain this.
Lutein from conventional supplements is much more poorly absorbed than lutein from eggs, which are rich in phospholipids. This human trial found that taking lutein with phospholipids increased the blood levels of lutein much more than taking lutein alone.
This review discusses the strategies for improving iron status in female athletes. Instead of taking iron supplements, studies suggest that dietary changes may be more effective.
The time of day that eating occurs has been thought to impact phosphorus levels in blood. This crossover trial suggests that nighttime eating may increase phosphorus levels by blocking nighttime phosphorus excretion.
This rat study suggests that a diet high in quercetin, a common plant compound, may protect against obesity-related fatty liver.